Flexible liquid-packaging such as pouches are used to package many consumer goods, particularly food and beverages. The term “liquid-packaging” is understood by those skilled in the art to refer to both liquids and other flowable materials or product.
Generally, it is important to obtain optimal fill-accuracy of the flowable material in flexible liquid-packaging pouches. By “optimal” or “optimized” is meant that the variation in fill-accuracy of the product amount in the pouch is generally minimized without sacrificing other critical factors acceptable for packaging use.
This invention relates to improving fill-accuracy, that is, reducing over-fill and under-fill of the pouch. Improving fill-accuracy is important for several reasons, for example, reduction in packaging cost and for complying with government regulations. For example, many states require that an advertised product quantity must be the minimum product quantity contained in a package. Thus, if the fill-accuracy is poor, a vendor must fill the pouch with product amount more than what is advertised, which raises the business cost. Controlling fill-accuracy can therefore help minimize product waste for the vendor.
Several methods are known to those skilled person for delivering product to a package. For example, a flow of material can be established for a period of time filling an open container. In the alternative, a flowmeter can be used to measure the product flow into a container. In the present embodiment, a constant product head is established in a balance tank above the outlet of the balance tank. This configuration provides a constant flow of product into pouches produced on a vertical form fill seal (“VFFS”) machine. Once the product fills the first pouch, by a pinching mechanism, the first pouch is separated with the subsequent pouch being filed with the product. The timing of this mechanism and the product flow dictate the product volume in each pouch. Fill-accuracy is predicated on the repeatability of the timing of the pinching mechanism, and on the consistency of the flow.
It is an object of the present invention to improve the consistency of the flow from the balance tank to the pouch. Specifically, the present invention provides a process, apparatus, and a pouch with improved fill-accuracy over the conventional process.